Tire containing sealer

ABSTRACT

In a sealant-containing tire, an outer liner is fastened to an inner surface of a tread of a tire body, and a sealant chamber that is filled with sealant is defined between a central part of an inner linear and an inner surface of an outer liner by fastening left and right ends of an inner linear to an inner surface of a side wall of a tire body. The tire body comprises a mixture of butyl rubber and natural rubber, or a mixture of butyl rubber and acrylonitrile butadiene rubber, the outer liner comprises natural rubber, and the inner liner comprises butyl rubber. The sealant chamber can therefore be reliably formed without the outer liner and the inner liner becoming fastened together during vulcanization molding without employing an anti-sticking agent or an anti-sticking sheet.

FIELD OF THE INVENTION

The present invention relates to a sealant-containing tire having anannular sealant chamber defined by a liner at an inner surface of atread of a tire body.

BACKGROUND ART

Sealant-containing tires such as disclosed in Japanese PatentApplication Laid-open No. 8-323875, where a sealant chamber at leastpartially defined by a liner is formed at an inner surface of a tread ofa tire body so that punctures in the tread caused by nails etc. areautomatically sealed by sealant contained within the sealant chamber soas to delay the leaking of air from the puncture, are well known.

With this related sealant-containing tire, when the liner is overlaid onthe tire body prior to vulcanization molding, vulcanization molding iscarried out with part of the contact surfaces of both the tire body andthe liner, or parts of contact surfaces of liners, being applied with ananti-sticking agent such as talcum powder etc. When the tire body isthen fastened through vulcanization to the tire body so as to form asingle body, a sealant chamber is formed as a result of portions towhich the anti-sticking agent has been applied remaining in anunfastened state. Other methods where, rather than using theanti-sticking agent, an anti-sticking sheet is sandwiched between thetire body and part of the liner contact surface or is sandwiched betweenparts of the contact surfaces of liners, are also well known.

However, applying an anti-sticking agent or sandwiching an anti-stickingsheet when overlaying a liner on a tire body prior to vulcanizationmolding in the tire manufacturing process causes both the number ofprocesses and the cost to increase, and it would therefore be preferableto develop a sealant containing tire where a sealant chamber can beformed without using an anti-sticking agent or anti-sticking sheet.

DISCLOSURE OF THE INVENTION

In order to resolve the aforementioned problems, it is therefore theobject of the present invention to accurately form a sealant chamber ofa sealant-containing tire without employing an anti-sticking agent oranti-sticking sheet.

In order to achieve the aforementioned object, according to the presentinvention, a sealant-containing tire with an annular sealant chamberformed at an inner surface of a tread of a tire body, and with theinside of the sealant chamber being filled with sealant, thesealant-containing tire comprises an outer liner fastened to the innersurface of the tread of the tire body, and an inner liner with left andright ends fastened to the inner surface of a side wall of the tire bodyso that a sealant chamber is defined between a central part of the innerliner and the inner surface of the outer liner. Here, the outer linerand the inner liner are composed of materials having anti-stickingproperties.

According to the above configuration, a sealant chamber can be reliablyformed without using an anti-sticking agent or anti-sticking sheet sothat both the number of steps and costs are reduced because a sealantchamber is defined between the central part of an inner liner and aninner surface of an outer liner by fastening the outer liner to theinner surface of the tread of the tire body and fastening the left andright ends of the inner liner to the inner surface of the side wall ofthe tire body and because the outer wall liner and the inner wall linerare composed of materials having anti-sticking properties.

In addition to the above configuration, there is proposed asealant-containing tire where the tire body comprises a mixture of atleast butyl rubber and natural rubber, or at least butyl rubber andacrylonitrile-butadiene rubber, with the outer liner being formed mainlyof natural rubber, and the inner liner being composed mainly of butylrubber.

According to this configuration, adhesiveness between the inner linerand the tire body, and between the outer liner and the tire body can bemaintained while having anti-sticking properties between the outer linerand the inner liner because the tire body comprises a mixture of atleast butyl rubber and natural rubber, or at least butyl rubber andacrylonitrile-butadiene rubber, with the outer liner being formed mainlyof natural rubber, and the inner liner being composed mainly of butylrubber.

According to the present invention, there is proposed asealant-containing tire with an annular sealant chamber formed at aninner surface of a tread of a tire body, and with the inside of thesealant chamber being filled with sealant, the sealant-containing tirecomprising an outer liner fastened to the inner surface of a side wallof the tire body, and an inner liner with left and right ends fastenedto the inner surface of the outer liner so that a sealant chamber isdefined between a central part of the inner liner and the inner surfaceof the side wall. Here, the inner liner and the tire body are composedof materials having anti-sticking properties.

According to the above configuration, a sealant chamber can be reliablyformed without using an anti-sticking agent or anti-sticking sheet sothat both the number of steps and costs are reduced because a sealantchamber is defined between the central part of the inner liner and theinner surface of the tread of the tire body by fastening the outer linerto the inner surface of the side walls of the tire body and fasteningthe left and right ends of the inner liner to the inner surface of theouter liner and because the inner liner and tire body are composed ofmaterial having anti-sticking properties.

According to the present invention, there is proposed asealant-containing tire with an annular sealant chamber formed at aninner surface of a tread of a tire body, and with the inside of thesealant chamber being filled with sealant, the sealant-containing tirecomprising a first outer liner, fastened to the inner surface of thetread of the tire body, a second outer liner fastened to the innersurface of a side wall of the tire body, and an inner liner with leftand right ends fastened to the inner surface of the second outer linerso that a sealant chamber is defined between a central part of the innerliner and the inner surface of the first outer liner. Here, the firstouter liner and the inner liner are composed of materials havinganti-sticking properties.

According to the above configuration, a sealant chamber can be reliablyformed without using an anti-sticking agent or anti-sticking sheet sothat both the number of steps and costs are reduced because a sealantchamber is defined between the central part of the inner liner and theinner surface of the first outer liner by fastening the first outerliner and the second outer liner to the inner surface of a tread and theside walls of a tire body, respectively, and fastening left and rightends of the inner liner to the inner surface of the second outer liner,and because the first outer liner and the inner liner are composed ofmaterials having anti-sticking properties.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 to FIG. 5 show a first embodiment of the present invention, whereFIG. 1 is a lateral cross-section of a wheel mounted with a tire,

FIG. 2 is a view (first of two) of a process for manufacturing a tire,

FIG. 3 is a view (second of two) of a process for manufacturing a tire,

FIG. 4 is an enlarged cross-section along line 4—4 of FIG. 2, and

FIG. 5 is an enlarged cross-section along line 5—5 of FIG. 3,

FIG. 6 is a lateral cross-section of a wheel mounted with a tirerelating to a second embodiment of the present invention,

FIG. 7 is a view corresponding to FIG. 4, relating to a secondembodiment of the present invention,

FIG. 8 is a lateral cross-section of a wheel mounted with a tirerelating to a third embodiment of the present invention, and

FIG. 9 is a view corresponding to FIG. 4, relating to a third embodimentof the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

The following is a description of practical examples of the presentinvention based on embodiments of the present invention shown in theappended drawings.

FIG. 1 to FIG. 5 show a first embodiment of the present invention.

As shown in FIG. 1, a tubeless tire T comprising a tire body 1, an outerliner 2 fastened by vulcanization to the inner part of the tire body 1,and an inner liner 3 is mounted on a motorcycle wheel rim R. The outerliner 2 is fastened by vulcanization to the inner surface of a tread 4of the tire body 1 and the left and right ends of the inner liner 3excluding the central part are fastened by vulcanization to the innersurfaces of left and right side walls 5, 5 of the tire body 1. A sealantchamber 7 substantially arc-shaped in cross-section that is filled withsealant 6 is defined between the central part of the inner liner 3 andthe outer liner 2 and an air chamber 8 substantially circular incross-section is defined within the inner liner 3.

The rim R is equipped with an annular rim body 9 extending in acircumferential direction of the tire T, and a pair of flanges 10, 10,extending radially outwards in a widthwise direction from both ends ofthe rim body 9, for supporting the inner periphery of the tire body 1.An air valve 11 for filling the air chamber 8 with air is supported soas to pass through an air valve attachment section 12 formed at onelocation in the circumferential direction of the rim body 9.

The sealant chamber 7 is held in shape along the inner surface of thetread 4 by the air pressure of the air chamber 8. Therefore, even if thetire body 1 is punctured in a radial direction or from the side by anail, etc., the sealant 6 immediately fills the puncture so as to repairthe puncture, and the leaking of air from the air chamber 8 is delayed.The sealant 6 is also supported by the sealant chamber 7 and thereforedoes not flow to the air chamber 8, and the air valve 11 and pressuregauges etc. assigned to the air valve 11 do not become clogged.

The tire body 1 comprises a mixture including at least butyl rubber(IIR) and natural rubber (NR), or a mixture including at least butylrubber (IIR) and acrylonitrile butadiene rubber (NBR), with carcassfiber then being embedded within these mixtures. The outer liner 2 isformed mainly of natural rubber (NR) and the inner liner 3 is formedmainly of butyl rubber (IIR). The tire body 1 therefore has adhesivenesswith respect to both the outer liner 2 and the inner liner 3 but theouter liner 2 and the inner liner 3 both have anti-sticking propertieswith respect to each other, and are therefore difficult to attach toeach other through vulcanization.

Next, a description is given of the process for manufacturing the tire Tbased on FIG. 2 and FIG. 3.

The process for manufacturing the tire T comprises an inner linerwrapping step, an outer liner wrapping step, a tire raw materialwrapping step, a metal mold installation step, a vulcanization step, asealant filling step, and an inspection step.

First, in the inner liner wrapping step, the cylindrical inner liner 3is fitted to the outer periphery of a drum 23, and in the outer linerwrapping step, the outer liner 2 is wrapped around so as to be laid overthe outer periphery of the inner liner 3. The tire raw material 24 isthen formed by wrapping raw materials for each part of the tire body 1about the outer periphery of the inner liner 3 and the outer liner 2 inthe tire raw material wrapping step.

FIG. 4 shows a lateral cross-section of tire raw material 24 wrappedaround the drum 23. Here, the width W₂ of the outer liner 2 overlaid onthe outer side of the innermost positioned inner liner 3 of width W₁ issmall, and part of the inner liner 3 therefore projects from the leftand right ends of the outer liner 2.

The tire raw material 24 is constructed by wrapping the tire body 1comprising raw rubber about the outer periphery of the inner liner 3 andthe outer liner 2. The tire body 1 comprises a cord section 25 wrappedaround the outside of the inner liner 3 and the outer liner 2 in aradial direction, a pair of bead sections 26, 26 fitted around the outerperiphery of the inner liner 3 so as to continue on from both ends ofthe cord section 25 in an axial direction, and a top tread 27 wrappedaround the outside of the cord section 25 and the bead sections 26, 26so as to cover the cord section 25 and the bead sections 26, 26 in aradial direction.

The tire raw material 24 removed from the drum 23 is then installedbetween an upper mold 29 and a lower mold 30 for vulcanization moldingin the metal mold installation step. In the vulcanization step shown inFIG. 5, the upper mold 29 and lower mold 30 are heated, a blazer 31located within the tire raw material 24 is expanded using hot air, thetire raw material 24 is made to fit tightly with the molding surfaces ofthe upper mold 29 and the lower mold 30, and vulcanization molding isthen performed to give the shape of the finished product. In thisvulcanization molding, the inner liner 3 and the outer liner 2 arefastened by vulcanization to the tire body 1 so as to give a singlebody.

At this time, the tread 4 of the tire body 1 comprised of a mixture ofbutyl rubber (IIR) and natural rubber (NR), or a mixture of butyl rubber(IIR) and acrylonitrile butadiene rubber (NBR) is fastened byvulcanization to the outer liner 2 comprised of natural rubber (NR), andthe side walls 5,5 of the tire body 1 are fastened by vulcanization tothe inner liner 3 comprised of butyl rubber (IIR). However, the outerliner 2 formed of natural rubber (NR) and the inner liner 3 formed ofbutyl rubber (IIR) have anti-sticking properties with respect to eachother and therefore do not become fastened through vulcanization. Thismeans that the sealant chamber 7 can be defined between the outer liner2 and the inner liner 3. Further, unevenness exists at the inner surfaceof the tread 4 of the tire body 1 embedded with carcass fiber but thefluidity of the sealant 6 can be increased and the sealing effectimproved by removing this unevenness by fastening the outer liner 2.

A sealant chamber 7 of a precise shape can therefore be formed withoutemploying an anti-sticking agent or anti-sticking sheet by suitablyselecting the properties of the rubber of the tire body 1, the outerliner 2 and the inner liner 3, and the number of steps and the cost canbe reduced accordingly.

When the vulcanization molding is complete and the outer liner 2 and theinner liner 3 that are now integrally formed with the tire body 1 aretaken out of the metal mold, the inside of the sealant chamber 7 isfilled with the sealant 6 using a syringe, etc. in the sealant filledstep so that the tire T is completed. The completed product is theninspected in an inspection step so as to complete all of the steps.

The following is a description based on FIG. 6 and FIG. 7 of a secondembodiment of the present invention.

The second embodiment of the tire T differs from the first embodimentwith regards to the positioning of fastening outer liners 2, 2 to thetire body 1, i.e. in the first embodiment, an outer liner 2 is fastenedto the inner surface of the tread 4 of the tire body 1 but in the secondembodiment, outer liners 2, 2 are fastened to the inner surfaces of leftand right side walls 5, 5 of the tire body 1. The sealant chamber 7 isthen defined between the inner surface of the tread 4 of the tire body 1and the central part of the inner liner 3 by fastening the left andright ends of the inner liner 3 to the inner surfaces of the left andright outer liners 2, 2.

The outer liners 2, 2 are composed of rubber that is adhesive withrespect to both the tire body 1 and the inner liner 3, and the innerliner 3 is composed of rubber that is adhesive with respect to the outerliners 2, 2 but has anti-sticking properties with respect to the tirebody 1.

In order to manufacture the tire T having the aforementioned structure,in a tire raw material wrapping step shown in FIG. 7, after the innerliner 3 is wrapped around the outer periphery of the drum 23, the pairof outer liners 2, 2 are wrapped around the left and right ends of theinner liner 3. The tire body 1 comprised of raw rubber is then wrappedaround the outer periphery so as to form the tire raw material 24, thistire raw material 24 is installed in a metal mold, and vulcanizationmolding is carried out. As a result, the outer liners 2, 2 becomefastened by vulcanization to the inner surfaces of the side walls 5, 5of the tire body 1, the left and right ends of the inner liner 3 becomefastened by vulcanization to the inner surface of the outer liners 2, 2but the tread 4 of the tire body 1 and the central part of the innerliner 3 do not become fastened together. A sealant chamber 7 cantherefore be defined between the tread 4 and the inner liner 3 withoutemploying an anti-sticking agent or a anti-sticking sheet.

The following is a description of a third embodiment of the presentinvention based on FIG. 8 and FIG. 9.

The third embodiment of the tire T differs from the first embodiment andthe second embodiment in that this third embodiment of a tire T isequipped with a first outer liner 2 ₁ and second outer liners 2 ₂, 2 ₂,i.e. in the third embodiment, the first outer liner 2 ₁ is fastened tothe inner surface of the tread 4 of the tire body 1, the second outerliners 2 ₂, 2 ₂ are fastened to the inner surfaces of the left and rightside walls 5, 5 of the tire body 1, and the left and right ends of theinner liner 3 are fastened to the inner surfaces of the second outerliners 2 ₂, 2 ₂. The sealant chamber 7 can therefore be defined betweenthe inner surface of the first outer liner 2 ₁ and the central part ofthe inner liner 3.

The first outer liner 2, is formed of a rubber that is adhesive withrespect to the tire body 1 but has anti-sticking properties with respectto the inner liner 3. The second outer liners 2 ₂, 2 ₂ are formed ofrubber having adhesiveness with respect to both the tire body 1 and theinner liner 3. The inner liner 3 is formed of a rubber havinganti-sticking properties with respect to the first outer liner 2, but isadhesive with respect to the second outer liners 2 ₂, 2 ₂.

In order to manufacture the tire T of the above structure, in the tireraw material wrapping step shown in FIG. 9, after the inner liner 3 iswrapped around the outer periphery of the drum 23, one first outer liner2 ₂ and two second outer liners 2 ₂, 2 ₂ are wrapped around the centralpart of the central part, and left and right ends respectively, of theinner liner 3. The tire body 1 comprising raw rubber is then wrappedaround the outer periphery so as to form the tire raw material 24, thetire raw material 24 is installed in the metal mold, and vulcanizationmolding is carried out. As a result, the first outer liner 2 ₁ isfastened by vulcanization to the inner surface of the tread 4 of thetire body 1, the second outer liners 2 ₂, 2 ₂ are fastened byvulcanization to the inner surfaces of the side walls 5, 5, the left andright ends of the inner liner 3 are fastened by vulcanization to theinner surfaces of the second outer liners 2 ₂, 2 ₂ and the first outerliner 2 ₁ and the central part of the inner liner 3 remain unfastened.The sealant chamber 7 can therefore be defined between the first outerliner 2 ₁ and the inner liner 3 without employing an anti-sticking agentor an anti-sticking sheet.

Embodiments of the present invention are described above but variousdesign modifications are possible without deviating from the spirit ofthe present invention.

INDUSTRIAL APPLICABILITY

As is apparent from the above, the sealant-containing tire according tothe present invention is applicable to a two-wheeled motor vehicle andfurther to other types of vehicles, e.g., a bus, a truck or anautomobile.

1. A sealant-containing tire with an annular sealant chamber formed atan inner surface of a tread of a tire body, and with the inside of thesealant chamber being filled with sealant, wherein saidsealant-containing tire comprises: an outer liner directly fastened tothe inner surface of a side wall of the tire body; and an inner linerwith left and right ends directly fastened to the inner surface of theouter liner so that a sealant chamber is defined between a central partof the inner liner and the inner surface of the tread, said sealantchamber containing the sealant, which sealant directly contacts thetread, wherein the inner liner and the tire body are composed ofmaterials having anti-sticking properties.
 2. A sealant-containing tirewith an annular sealant chamber formed at an inner surface of a tread ofa tire body, and with the inside of the sealant chamber being filledwith sealant, wherein said sealant-containing tire comprises: a firstouter liner directly fastened to the inner surface of the tread of thetire body; a second outer liner directly fastened to the inner surfaceof a side wall of the tire body; and an inner liner with left and rightends fastened to the inner surface of the second outer liner so that asealant chamber is defined between a central part of the inner liner andthe inner surface of the first outer liner, wherein the first outerliner and the inner liner are composed of materials having anti-stickingproperties.